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From: Linus Walleij <linus.walleij@linaro.org>
To: Brad Larson <brad@pensando.io>, Mark Brown <broonie@kernel.org>,
	Serge Semin <fancer.lancer@gmail.com>
Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Olof Johansson <olof@lixom.net>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	linux-spi <linux-spi@vger.kernel.org>,
	linux-mmc <linux-mmc@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/8] gpio: Add Elba SoC gpio driver for spi cs control
Date: Sun, 29 Aug 2021 23:09:19 +0200	[thread overview]
Message-ID: <CACRpkdZEURRTe15HGf93SvyHej=_6qhfP9KWPSQbCM=SLUVKmA@mail.gmail.com> (raw)
In-Reply-To: <CAK9rFnzDZ4MNm68AJ75g7zegLD-7UMHyoVR-4ssitYTTEeQm5g@mail.gmail.com>

On Mon, Aug 23, 2021 at 3:06 AM Brad Larson <brad@pensando.io> wrote:

> The gpio pins being used for the Elba SoC SPI CS are dedicated to this
> function.  Are you recommending that the code in
> drivers/gpio/gpio-elba-spics.c be integrated into
> drivers/spi/spi-dw-mmio.c?

That makes most sense does it not?

Special purpose pins should be managed by that special purpose
hardware driver, DW SPI in this case.

The compatible string etc should be enough to determine that we
need some extra GPIO control here, possibly specify extra registers
for the SPI host etc.

The struct spi_master has a special callback .set_cs() and you
should make this behave special for your special hardware.
In the case of the DW driver it appears that even subdrivers can
pass a custom version of this call in struct dw_spi.

Yours,
Linus Walleij

WARNING: multiple messages have this Message-ID (diff)
From: Linus Walleij <linus.walleij@linaro.org>
To: Brad Larson <brad@pensando.io>, Mark Brown <broonie@kernel.org>,
	 Serge Semin <fancer.lancer@gmail.com>
Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Arnd Bergmann <arnd@arndb.de>,
	 Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	 Ulf Hansson <ulf.hansson@linaro.org>,
	Olof Johansson <olof@lixom.net>,
	 "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	linux-spi <linux-spi@vger.kernel.org>,
	 linux-mmc <linux-mmc@vger.kernel.org>,
	 "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
	<devicetree@vger.kernel.org>,
	 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/8] gpio: Add Elba SoC gpio driver for spi cs control
Date: Sun, 29 Aug 2021 23:09:19 +0200	[thread overview]
Message-ID: <CACRpkdZEURRTe15HGf93SvyHej=_6qhfP9KWPSQbCM=SLUVKmA@mail.gmail.com> (raw)
In-Reply-To: <CAK9rFnzDZ4MNm68AJ75g7zegLD-7UMHyoVR-4ssitYTTEeQm5g@mail.gmail.com>

On Mon, Aug 23, 2021 at 3:06 AM Brad Larson <brad@pensando.io> wrote:

> The gpio pins being used for the Elba SoC SPI CS are dedicated to this
> function.  Are you recommending that the code in
> drivers/gpio/gpio-elba-spics.c be integrated into
> drivers/spi/spi-dw-mmio.c?

That makes most sense does it not?

Special purpose pins should be managed by that special purpose
hardware driver, DW SPI in this case.

The compatible string etc should be enough to determine that we
need some extra GPIO control here, possibly specify extra registers
for the SPI host etc.

The struct spi_master has a special callback .set_cs() and you
should make this behave special for your special hardware.
In the case of the DW driver it appears that even subdrivers can
pass a custom version of this call in struct dw_spi.

Yours,
Linus Walleij

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-08-29 21:09 UTC|newest]

Thread overview: 102+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-04  3:41 [PATCH 0/8] Support Pensando Elba SoC Brad Larson
2021-03-04  3:41 ` Brad Larson
2021-03-04  3:41 ` [PATCH 1/8] gpio: Add Elba SoC gpio driver for spi cs control Brad Larson
2021-03-04  3:41   ` Brad Larson
2021-03-04  8:29   ` Linus Walleij
2021-03-04  8:29     ` Linus Walleij
2021-03-04  9:10     ` Serge Semin
2021-03-04  9:10       ` Serge Semin
2021-03-04 13:38       ` Linus Walleij
2021-03-04 13:38         ` Linus Walleij
2021-08-23  1:05         ` Brad Larson
2021-08-23  1:05           ` Brad Larson
2021-08-29 21:09           ` Linus Walleij [this message]
2021-08-29 21:09             ` Linus Walleij
2021-10-04 16:46             ` Brad Larson
2021-10-04 16:46               ` Brad Larson
2021-10-12 23:51               ` Linus Walleij
2021-10-12 23:51                 ` Linus Walleij
2021-10-14 20:06                 ` Brad Larson
2021-10-14 20:06                   ` Brad Larson
2021-03-30  2:44     ` Brad Larson
2021-03-30  2:44       ` Brad Larson
2021-08-23  1:05     ` Brad Larson
2021-08-23  1:05       ` Brad Larson
2021-03-04 20:43   ` Elliott, Robert (Servers)
2021-03-04 20:43     ` Elliott, Robert (Servers)
2021-08-23  1:06     ` Brad Larson
2021-08-23  1:06       ` Brad Larson
2021-03-05 11:25   ` Krzysztof Kozlowski
2021-03-05 11:25     ` Krzysztof Kozlowski
2021-08-23  1:07     ` Brad Larson
2021-08-23  1:07       ` Brad Larson
2021-03-05 13:57   ` Geert Uytterhoeven
2021-03-05 13:57     ` Geert Uytterhoeven
2021-08-23  1:08     ` Brad Larson
2021-08-23  1:08       ` Brad Larson
2021-03-07 19:21   ` Andy Shevchenko
2021-03-07 19:21     ` Andy Shevchenko
2021-03-29  1:19     ` Brad Larson
2021-03-29  1:19       ` Brad Larson
2021-03-29 10:39       ` Andy Shevchenko
2021-03-29 10:39         ` Andy Shevchenko
2021-08-23  1:13         ` Brad Larson
2021-08-23  1:13           ` Brad Larson
2021-08-23  7:50           ` Geert Uytterhoeven
2021-08-23  7:50             ` Geert Uytterhoeven
2021-08-23 16:30             ` Brad Larson
2021-08-23 16:30               ` Brad Larson
2021-08-23 20:11               ` Geert Uytterhoeven
2021-08-23 20:11                 ` Geert Uytterhoeven
2021-10-04 17:14                 ` Brad Larson
2021-10-04 17:14                   ` Brad Larson
2021-10-04 17:16                   ` Geert Uytterhoeven
2021-10-04 17:16                     ` Geert Uytterhoeven
2021-08-23  1:10     ` Brad Larson
2021-08-23  1:10       ` Brad Larson
2021-03-04  3:41 ` [PATCH 2/8] spi: cadence-quadspi: Add QSPI support for Pensando Elba SoC Brad Larson
2021-03-04  3:41   ` Brad Larson
2021-03-04  9:29   ` Arnd Bergmann
2021-03-04  9:29     ` Arnd Bergmann
2021-03-04  3:41 ` [PATCH 3/8] spi: dw: Add support for Pensando Elba SoC SPI Brad Larson
2021-03-04  3:41   ` Brad Larson
2021-03-04  6:44   ` Serge Semin
2021-03-04  6:44     ` Serge Semin
2021-08-23  1:17     ` Brad Larson
2021-08-23  1:17       ` Brad Larson
2021-03-04  8:48   ` Linus Walleij
2021-03-04  8:48     ` Linus Walleij
2021-03-10  3:52     ` Brad Larson
2021-03-10  3:52       ` Brad Larson
2021-03-04  3:41 ` [PATCH 4/8] spidev: Add Pensando CPLD compatible Brad Larson
2021-03-04  3:41   ` Brad Larson
2021-03-04  9:33   ` Arnd Bergmann
2021-03-04  9:33     ` Arnd Bergmann
2021-03-04  3:41 ` [PATCH 5/8] mmc: sdhci-cadence: Add Pensando Elba SoC support Brad Larson
2021-03-04  3:41   ` Brad Larson
2021-03-04  9:41   ` Arnd Bergmann
2021-03-04  9:41     ` Arnd Bergmann
2021-03-04  3:41 ` [PATCH 6/8] arm64: Add config for Pensando SoC platforms Brad Larson
2021-03-04  3:41   ` Brad Larson
2021-03-04  9:42   ` Arnd Bergmann
2021-03-04  9:42     ` Arnd Bergmann
2021-03-04  3:41 ` [PATCH 7/8] arm64: dts: Add Pensando Elba SoC support Brad Larson
2021-03-04  3:41   ` Brad Larson
2021-03-04  8:03   ` Serge Semin
2021-03-04  8:03     ` Serge Semin
2021-03-29  1:07     ` Brad Larson
2021-03-29  1:07       ` Brad Larson
2021-08-23  0:54     ` Brad Larson
2021-08-23  0:54       ` Brad Larson
2021-03-04  8:51   ` Linus Walleij
2021-03-04  8:51     ` Linus Walleij
2021-03-29  0:54     ` Brad Larson
2021-03-29  0:54       ` Brad Larson
2021-03-04  9:06   ` Arnd Bergmann
2021-03-04  9:06     ` Arnd Bergmann
2021-03-04 20:47   ` Rob Herring
2021-03-04 20:47     ` Rob Herring
2021-03-05 11:22   ` Krzysztof Kozlowski
2021-03-05 11:22     ` Krzysztof Kozlowski
2021-03-04  3:41 ` [PATCH 8/8] MAINTAINERS: Add entry for PENSANDO Brad Larson
2021-03-04  3:41   ` Brad Larson

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